Method of making hollow head valves



www@ y Feb', il w36. 'A. T. coLwELL METHOD OF MAKING HOLLOW HEAD VALVESOriginal Filed Feb. 19, 193.1,

n f O Y Patented Feb. 11, 1936 UNITED STATES PATENT oFFlcl:

METHOD OF MAKING HOLLOW HEAD VALVES Original application February 19,1931, Serial No.

516,882, now Patent No. 1,984,728, dated December 18, 1934.

Divided and this application November 19, 1934, Serial No. 753,595

7 Claims.

Great difliculty has been encountered in theV manufacture of valves forinternal combustion engines that are capable of withstanding the hightemperatures to which such a member is subjected, and at the same timemaintaining the manufacturing cost on an economical basis. Many valveshave been made of a special alloy capable of resisting heat, but thecost of this alloy lis excessive. Valves having cooling mediums therein,such as sodium or salt, have also been produced, and have been found tobe advantageous in conducting heat from those parts of the valve whichcontact the hot exhaust gases of the internal combustion engine to thecooler parts of the valve. Universal use of sodium or salt cooled valveshas been prevented by manufacturing costs and also by a lack ofuniformity and foolproofness in their manufacture.

It is an object of this invention to provide a process for producinghollow valves adapted to receive a cooling medium therein, which processis economical and foolproof.

It is a further object of this invention to provide improvements inmethods of making hollow head valves whereby the valves may be formedfrom a cup-shaped blank which is produced in any manner by working theblank to collapse the shank portion thereof into a stem form, anddrilling out the stem to provide a chamber in communication with thechamber in the head portion.

It is a specific object of this invention to provide a valve adapted toreceive a cooling medium therein by a method which comprises forming acup-shaped blank which has been produced in any manner to provide anarticle having a head and stem portion, then drilling the stem portionto provide an aperture therethrough which is adapted to receive acooling medium therein, and

finally reworking the end of the stem to seal the cooling medium in thevalve.

Other and further objects of this invention will be apparent from thefollowing description and the appended claims.

This invention (in a preferred form, is illustrated in the followingspecification 'and the accompanying drawing which form a part of thisspeciiication.

On the drawing: l

Figure 1 is a central cross-sectional view of a blank used in making avalve according to the process of this invention.

Figure 2 is a central cross-sectional view showing the blank of Figure 1worked to form a head 15 and stem thereon.

Figure V3 is a central cross-sectional view of the worked blank shown inFigure 2, with a bore extending through the stem portion thereof.

Figure 4 is a central cross-sectional View show- 20 ing the partlyfinished valve with a bridge formed in the stem portion thereof.

Figure 5 is a central cross-sectional view similar to Figure 4, showingthe incompleted valve after the end has been reworked and apertures have25 been bored in the end and bridge members.

Figure 6 is a central cross-sectional view showing a completed valveprepared according to the process of this invention.

As shown on the drawing:

In Figure 1, the blank I having a cylindrical` shank portion 2 and anenlarged end 3 thereon is provided with a bore 4 extending therethroughin close proximity to the head end 3. The bore is preferably enlarged atthe head end as sho-Wn 35 at 5. The blank I may be formed by anysuitable method, as by forging or casting.

The shank portion 2 of the blank I is next worked to form an elongatedstem portion 6. a, During the working operation, the Walls of the shank2 are collapsed together as shown in Figure 2 so that the stem portion 6formed thereby is a solid wall. The stem forming operation is preferablyaccomplished by heating and forging 45 the valve blank I. 'Iheenlargedbore5 of the blank I provides a hollow chamber I while theenlarged end v3 of the blank I forms the valve and 8. During the sternforming operation, thickened portions '9 and I0 are preferably formed onthe stern in- 50 `diurn wet the inside of the valve when heatedtermediate the end of the stem and at the end of the stem as shown inFigure 2. The so formed blank is then bored with a suitable drill so asto form a passage II through the stem, which passage communicates withthe chamber 'I in the head end of the blank.

The thickened portions 9 and I0 are next reheated and worked to form abridge I2 from the thickened portion 9 and a closed end portion I3 fromthe thickened portion I0. That portion of the bore II between the bridgeI2 and the end I3 provides a separate chamber I4 as shown in Figure 4.

As shown in Figure 5, the end I3 is drilled to provide an aperture I5extending therethrough while the bridge I2 is drilled to provide atapered bore I6 therethrough.

The head 8 of the Valve blank is next provided with a seating surfaceI'I as shown in Figure 6, and an annular groove I8 extending around thetop surface of the head. The finished valve head, however, can be formedwithout the groove I8 and with other forms of seating surfaces.

The chamber II of the valve stem and the chamber I of the valve headcooperating therewith are then partially filled with a cooling mediumI9, and a plug 2@ is inserted in the aperture of the bridge I2. The plug2B is preferably force fitted into the bridge aperture to seal thecompartments 'I and I I. The cooling medium may be any substance whichhas a heat conductivity greater than the heat conductivity of the metalof the valve. The cooling medium I9 is preferably a liquid state attemperatures above about 200 F. It is desirable that the cooling metothe liquefying temperature, so that a good thermal contact is obtained.Metallic sodium and metal salts, such as lithium nitrate and potassiumnitrate have been used with great success.

The end I3 of the valve is next threaded as shown at2I and a groove 22is formed above the threaded portion 2|. The groove 22 is adapted toreceive a valve spring retainer lock. vIf desired, a cooling medium 23may be inserted to partially fill the chamber I4. It should beunderstood, however, that this chamber may be left as a dead space, ormay be lled with some medium for carrying oif heat, such as water. Aplug 24 having a head 25 is inserted into the aperture I5 of the end I3and is preferably welded therein so as to permanently close the chamberI4. 'Ihe head 25 of the plug 24 is pref- -erably formed of a hard steelalloy capable of `munication with the chamber in the head. The

method of this invention is simple, expedient, and economical. It isalso adapted for mass production with standard equipment.

- I am aware that numerous details of the proc- .ess may be variedthrough a wide range without departing from the principles of thisinvention, and I, therefore, do no-t purpose limiting the patent grantedhereon otherwise than necessitated by .the prior art.

I rclaim as my invention:

l. The method of making a valve which comprises forming a cup-shapedblank with an enlarged bottom, the recess in the cup-shaped blank beingalso enlarged at the bottom, forging said cup-shaped blank so as to forma head with a cavity therein and a solid stem portion extendingtherefrom and so as to leave a thickened portion adjacent the end andintermediate the head and end of the stem, drilling out said stem,reworking the stem so vas to form partitions from the thickened portionsat the end and intermediate the end and head of the valve, boringapertures through said partitions, introducing a fusible cooling mediuminto the valve, land. plugging up the apertures in said partitions.

2. The method of making a valve which comprises forming a cup-shapedblank, working the blank to form a head with a cavity therein and asolid stem portion extending therefrom, drilling out said stem portionto provide a chamber therein in communication with the cavity in thehead, and closing the end of the stem.

3. The method of making a valve which comprises forming a cup-shapedblank having shank walls defining a cylindrical chamber and an enlargedbottom defining an enlarged recess in communication with said chamber,collapsing the shank walls to conne a cavity in the bottom of the blankand elongating said walls to providev a solid stem portion, drilling outsaid stem portion to provide a chamber therein in communication With thecavity in the head, and sealing the end of the stem.

4. The process of making a hollow head Valve which comprises forming acup-shaped blank with an enlarged bottom and having an enlarged recessin the bottom, working the blank to form a head with a cavity thereinand a solid stem portion extending therefrom, drilling out said stemportion to provide a chamber therein in communication with the cavity inthe head, and closing the end of the stem to form a compartment adaptedto receive a cooling medium therein.

5. The process of making a hollow head and stem valve which comprisesforming a metal blank with cylindrical shank Walls defining acylindrical aperture, an enlarged end on said blank having an enlargedrecess therein, collapsing the shank walls together to conne a cavity inthe enlarged head portion, working the blank to provide an elongatedstem thereon, drilling out said stem to pro-vide a chamber therein incommunication with the cavity in the end portion thereof, and closingthe end of the stem to provide a compartment adapted to receive acooling medium therein.

6. The process of making a valve which comprises forming a cup-shapedblank with an enlarged bottom, the recess in the cup-shaped blank beingalso enlarged at the bottom, working the walls of the blank to form asolid stem portion thereon with thickened metallic portions adjacent theend and intermediate the head and end of the stem, drilling out thestem, reworking the stem so as to form partitions from the thickenedmetallic portions at the end and intermediate the end and head of thevalve, boring apertures through said partitions, introducing a fusiblecooling medium into the chamber formed between the head and partitionintermediate the ends of the valve stem, plugging the aperture in saidpartition, and sealing the end of the valve stem.

7. The process of making a lled Valve which comprises forming acup-shaped blank having an enlarged end and an enlarged recess in saidend, collapsing the Walls of said blank and working said collapsed Wallsto provide an elongated solid stem portion with thickened metal portionsintermediate the ends of the stem and adjacent the end of the stem,boring out said stem to provide an aperture extending therethrough,heating said thickened portions of the stem and Working the heatedportions to provide partitions in the stem, providing apertures in saidpartitions, introducing a fusible cooling medium into the compartmentformed in the valve stem, and plugging the partitions to seal thecooling medium therein.

ARCI-HE T. COLWELL.

